SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5521e5d74f0c4fde99c6d53d877d6dd087456c06d5f5ee400a7f0c4ec38ef65' 
  AND token = 'se54OR0wf1QvL9P7jWPx4mJVsO1CgLuhatxrOUXakEw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}